This impressive sight is also impressively hard to get to, requiring 4x4-only driving or horses. Nakum was a significant port on the Holmul river, a waterway that linked Tikal with the Caribbean coast, though it reached its cultural peak in the Late Classic Period, well past Tikal's prime. It's 17km north of Yaxhá, a 1½-hour drive over a rough road that's impassable from August to January. It's at its best between March and May.
Remote as this spot is, it's particularly exciting to find such a formidable group of structures here. The excavated section is not huge, but it packs a lot in. Major excavations of the site have recently been completed. Archaeological research focused on the predominance of talud-tablero-type structures (stepped building style, with alternating vertical and sloping sections) in the south section, suggests a connection with Teotihuacán in Mexico. The question remains why Nakum flourished during the Terminal Classic at a time when its contemporaries were collapsing all around it.
The site features two major architectural groups, the North and South Sectors, connected by a causeway; most of the excavated structures are in the latter. The most interesting of these, in the part dubbed the Plaza Central, features an unusually well-preserved roofcomb with a clearly visible mask. In tandem with the pyramidal structure opposite, it presumably served as some kind of astronomical observatory.
Moving south from the Plaza Central, you enter the South Acropolis, a walled compound on a raised platform comprising 12 courtyards surrounded by 33 buildings that housed palatial residences. This arrangement was in place around AD 900, though there is evidence that the site had been occupied for the previous 14 centuries. What's unique about some of the courtyards here, like Patio 1, is that they were completely enclosed by buildings, a layout not found elsewhere in the Maya world. Outside the South Acropolis to the east are stelae bearing dates from the 9th century, among the latest recorded dates in the Maya lowlands.
El Sombrero Eco-Lodge in Yaxhá can arrange horseback rides with a night spent sleeping in hammocks. To get here independently, you'll need a 4WD and a permit from the park's administration at Yaxhá. Should you wish to spend the night, Nakum has a handful of tent platforms, free of charge, but bring food and water.